Superoxide radicals have a protective role during H2O2 stress

Research output: Contribution to journalJournal articleResearchpeer-review

Geoffrey W Thorpe, Mayfebelle Reodica, Michael Jonathan Davies, Gino Heeren, Stefanie Jarolim, Bethany Pillay, Michael Breitenbach, Vincent J Higgins, Ian W Dawes

Reactive oxygen species (ROS) consist of potentially toxic, partly reduced oxygen species and free radicals. After H(2)O(2) treatment, yeast cells significantly increase superoxide radical production. Respiratory chain complex III and possibly cytochrome b function are essential for this increase. Disruption of complex III renders cells sensitive to H(2)O(2) but not to the superoxide radical generator menadione. Of interest, the same H(2)O(2)-sensitive mutant strains have the lowest superoxide radical levels, and strains with the highest resistance to H(2)O(2) have the highest levels of superoxide radicals. Consistent with this correlation, overexpression of superoxide dismutase increases sensitivity to H(2)O(2), and this phenotype is partially rescued by addition of small concentrations of menadione. Small increases in levels of mitochondrially produced superoxide radicals have a protective effect during H(2)O(2)-induced stress, and in response to H(2)O(2), the wild-type strain increases superoxide radical production to activate this defense mechanism. This provides a direct link between complex III as the main source of ROS and its role in defense against ROS. High levels of the superoxide radical are still toxic. These opposing, concentration-dependent roles of the superoxide radical comprise a form of hormesis and show one ROS having a hormetic effect on the toxicity of another.

Original languageEnglish
JournalMolecular Biology of the Cell
Volume24
Issue number18
Pages (from-to)2876-84
Number of pages9
ISSN1059-1524
DOIs
Publication statusPublished - Sep 2013
Externally publishedYes

    Research areas

  • Adaptation, Physiological, Cytochromes b, Cytoprotection, Electron Transport, Gene Expression Regulation, Enzymologic, Hydrogen Peroxide, Microbial Viability, Mitochondria, Mutation, Oxidative Stress, RNA, Messenger, Saccharomyces cerevisiae, Stress, Physiological, Superoxide Dismutase, Superoxides

ID: 128974215